4S20U Explosive reactive armour elements
The 4S20U explosive reactive armour elements are an improved and updated version of the
Soviet 4S20 elements which were used in Kontakt-1 ERA (installed on the Soviet T-64, T-72, T-
The principle of operation of 4S20U is this: when being penetrated by a shaped charge jet the
explosive detonates forcing metal plates of the 4S20U casing to distribute and shatter the
trajectory of a shaped charge jet.
The use of ERA protection equipped with the 4S20U elements allows to reduce the destructive
capacity of unitary RPG/SPG grenades (to 90%), shaped charges – up to 80%, ATGM – up to
60% (except tandem-charge). At the same time, the 4S20U elements are safely protected from
detonating upon penetration by small arms bullets.
An important advantage is that the 4S20U elements can be placed into previously installed
containers of Kontakt-1 ERA without any design changes. This makes the mounting process
faster and easier. Regardless of superficial resemblance, 4S20U outbalances the previous
versions due to a new formula of the explosive.
Our company both provides supplies of the 4S20U elements for previously installed Kontakt-1
ERA systems (as a substitution for the outdated ones) and elaborates the design
documentation for further installation of ERA systems on existing and new models of tanks.